1. Field of the Invention
The present invention generally relates to a technology for computer-aided designing (CAD). The present invention particularly relates to editing graphic data including a plurality of layers.
2. Description of the Related Art
CAD apparatuses have been widely used for improving efficiency of designing work. Moreover, the graphic data created with the CAD apparatuses are used in downstream operations, such as manufacturing processes, thereby further improving the efficiency. In CAD, one drawing is sometimes created by dividing it into a plurality of layers.
For example, Japanese Patent Application Laid-open No. H9-101982 discloses a technique of dividing one drawing into a layer including common portions and a layer including non-common portions. On the other hand, Japanese Patent Application Laid-open No. 2004-46396 discloses a technological idea that facilitates maintenance of graphic data by inputting drawing frame information, building frame information, parts information, and dimension information into separate layers.
However, because CAD apparatuses disclosed in Japanese Patent Application Laid-open Nos. H9-101982 and 2004-46396 enable a designer to edit graphic data by simply dividing the graphic data into layers, there is a possibility that the designer's operations to edit graphic data may turn complicated and worse for working efficiency.
In addition, a use of each layer cannot be defined quantitatively, so that the way of using a layer varies from designer to designer. If a third person modifies the graphic data, or if the graphic data is used in downstream operations, there is a possibility that a problem may arise.